What aspect of angiosperms did Charles Darwin find particularly puzzling, referring to it as an 'abominable mystery'?

• A. The sudden and rapid diversification of flowering plants in the fossil record
• B. The presence of chloroplasts in their cells
• C. Their ability to reproduce without seeds
• D. Their adaptation to aquatic environments

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the context of the question. Charles Darwin referred to an 'abominable mystery' in relation to angiosperms, which are flowering plants. This phrase highlights something Darwin found particularly puzzling about their evolutionary history.
2. Step 2: Analyze the options provided. The options include: (1) The sudden and rapid diversification of flowering plants in the fossil record, (2) The presence of chloroplasts in their cells, (3) Their ability to reproduce without seeds, and (4) Their adaptation to aquatic environments.
3. Step 3: Recall key biological concepts. Angiosperms are known for their rapid diversification during the Cretaceous period, which is evident in the fossil record. This sudden appearance and diversification were difficult to explain in Darwin's time, making it a significant evolutionary puzzle.
4. Step 4: Evaluate the other options. Chloroplasts are present in many plant cells, not unique to angiosperms. Angiosperms reproduce using seeds, not without them. While some angiosperms are adapted to aquatic environments, this is not a defining or puzzling feature of their evolution.
5. Step 5: Conclude that the correct answer is related to the evolutionary history of angiosperms. The 'abominable mystery' refers to the sudden and rapid diversification of flowering plants in the fossil record, which Darwin found difficult to explain.